The present invention relates to a frame for supporting a glass plate in a horizontal position during a tempering process.
There is known a so-called quick sag bend method, which is used for tempering vehicular window panes. In this method, a glass plate is heated, while it is conveyed in a heating furnace by a transporting roller. The glass plate is stopped in a second half of the heating furnace. Then, the glass plate is pressed against a bending mold, which is positioned above the glass plate, by blowing a high-temperature jet air against the glass plate, in order to bend the glass plate. After that, the glass plate is dropped on a supporting frame (a cold ring) having a shape conforming to the contour of the glass plate. Under this condition, a high-pressure quenching air is blown against the glass plate for tempering. However, the peripheral edge portion of the glass plate tends to become inferior in the tempered ratio as compared with the rest thereof, since it is in abutment with the supporting frame and thus may not receive the quenching air sufficiently.
U.S. Pat. Nos. 4,906,271 and 5,069,703, each corresponding to Japanese Patent JP-B2-2614907, disclose a supporting frame for supporting thereon a glass plate. This frame is punched in order to allow the passage of the quenching air therethrough. The frame is covered with a heat-resistant fabric.
U.S. Pat. No. 4,661,142, corresponding to French Patent FR 2572388, discloses another supporting frame including bearing members with bearing surfaces which support a glass sheet.
It is an object of the present invention to provide a frame for supporting a glass plate during a quenching of the glass plate, which is capable of achieving a smooth passage of a quenching air of the tempering.
According to the present invention, there is provided a frame for supporting a glass plate during a quenching of the glass plate. This frame comprises a supporting ring for supporting thereon the glass plate, and a heat-resistant fabric tensioned and covering a top surface of said supporting ring to allow the glass plate to rest on said heat-resistant woven fabric. The supporting ring has a shape substantially conforming to a contour of the glass plate. A quenching air of the tempering is allowed to pass smoothly toward a peripheral portion of the glass plate by tensioning the heat-resistant fabric. With this, it becomes possible to improve the peripheral portion of the glass plate in strength and to prevent deformation and the like of the peripheral portion.